Draw tape bag

Abstract

The plastic bag with a hem and draw tape may include flexible thermoplastic sidewalls that have a network pattern imparted onto them across the side seams. In one embodiment, the network pattern is below the hem seal. In another embodiment, the network pattern covers the hem seal. The bag may also include a ribbed pattern below the network pattern. The network pattern may be continuous or discontinuous.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application No. 61 / 239,469, filed Sep. 3, 2009, which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates generally to bags having a draw tape. More particularly, the present invention relates generally to trash bags having a draw tape.[0004]2. Description of the Related Art[0005]Among their many applications, it is known to use thermoplastic bags as liners in trash or refuse receptacles. Trash receptacles that employ such liners may be found at many locations, such as, small household kitchen garbage cans. Bags that are intended to be used as liners for such refuse containers are typically made from low-cost, pliable thermoplastic material. When the receptacle is full, the thermoplastic liner actually holding the trash may be removed for further disposal and replaced with a new liner.[0006]It is d...

AI Technical Summary

Benefits of technology

[0009]In a further embodiment, the bag may be provided with additional features to help retain it to the trash canister. These features may include forming the thermoplastic sidewall material between the opposing sides to have a stretchable or yieldable characteristic or stretchable drawstring, for example as described in U.S. Pat. App. 20100046860 and incorporated by reference in its entirety herein. In one embodiment, the sidewall may be formed so that the sheet-like thermoplastic material bunches together as a series of wrinkles or creases. When a pulling force is applied, the bunched together thermoplastic material may un-bunch thereby allowing the bag to stretch or expand. The thermoplastic material may have some shape memory tending to cause the material to re-bunch together, thereby providing an elastic or resilient characteristic to the bag and helping the throat to grip or constrict around the canister. In another embodiment, the bag may have strips of elastic material attached to one or both of the sidewalls and may extend between the converging portions of the first and second side edges. Like the stretchable sidewall material, the strip of elastic material may help grip and retain the bag to the refuse canister.

[0010]In one embodiment, at least one sidewall may have a plurality of first ribs formed into the sidewall that have a first height. A second plurality of ribs may also be formed as a network pattern into the sidewall that have a second height that is different than the first height. The ribs and network pattern can lead to lower contact area in the trash can with the result that the filled bag is easier to remove from the trash can.

[0011]The plurality of second ribs may be arranged or gathered into discontinuous or differentiated network patterns of parallel, adjacent ribs that may be partially extensive with each other. The second ribs may be formed from thermoplastic material that has been displaced with respect to or stretched outwardly from the plane of the web used to form the bag. The unbending or flattening of the second ribs may expand the network thereby increasing the area of the sidewall and hence the volume of the bag so that the bag may accommodate larger or bulky items.

[0012]In another aspect, a thermoplastic web is provided which may be utilized in forming the bag or other items made from thermoplastic sheet material. The thermoplastic web may be processed through the first and second rollers described above to have a first plurality of ribs and a second plurality of ribs. Stretching of the thermoplastic material that accompanies formation of the first ribs may increase the overall area of the web. When a tensioning or pulling force is later applied to the web, the second ribs may unbend or flatten to increase the overall area of the web. The increase of the web area associated with formation of the first ribs provides more web material to process into finished goods. The increase in the web area associated with unbending of the second ribs provides the finished goods with an elastic or yieldable characteristic.

[0014]The bag may be produced by a high speed manufacturing process that processes continuous sheet-like webs of thermoplastic material into the finished bag via automated equipment. The process may include equipment, such as, seal bars, that the web or webs are directed between, that may form the side seals including the converging portions in a single, repeated step. Manufacturing the side seals in a single, repeated step may speed the manufacturing process and may reduce the cost of the finished bags.

Problems solved by technology

However, reducing the amount or quality of thermoplastic material forming the bag limits bag strength and toughness and makes the bag susceptible to tearing or rupture.

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